The present invention relates to an X-ray fluoroscopic/radiographic apparatus and, more particularly, to an improvement in a moving mechanism for moving a main carriage carrying an X-ray spot shot film for X-ray radiography thereon between the standby position and the photographing position in an X-ray fluoroscopic/radiographic apparatus having both functions of X-ray fluoroscopy utilizing an X-ray image detector such as an X-ray image intensifier (hereinafter abbreviated as I.I.) and of X-ray radiography utilizing X-ray film.
In an X-ray fluoroscopic/radiographic apparatus, an X-ray fluoroscopic image detected by an I.I. is monitored on a TV screen to perform fluoroscopic diagnosis. Then, X-ray radiography of the desired portion of the body of a patient is performed with an X-ray spot shot apparatus.
FIG. 1 shows a plan view of a moving mechanism of a main carriage 10 in the X-ray spot shot apparatus, and FIG. 2 shows a partial longitudinal sectional view thereof. Wheels 12, 14, 16 and 18 are axially supported to be rotatable at four positions of the main carriage 10. The wheels 12 and 14 are supported by a guide rail 20, the wheel 16 is supported by a guide rail 22, and the wheel 18 is supported by a guide rail 24. Referring to FIG. 1, the main carriage 10 is reciprocal along the directions indicated by the arrows X on the guide rail 20, 22 and 24 by a distance L between the standby position (hereinafter abbreviated as the F position) indicated by the solid line and the photographing position (hereinafter abbreviated as the R position) indicated by the broken line. A film supply and store device is arranged beneath the main carriage 10 at the F position. More specifically, a film magazine is arranged underneath the main carriage 10. A film drawn by suction from a suction cup is moved upward by a convey mechanism and is fed to an inner carriage (not shown) on the main carriage 10 from the side of the wheels 16 and 18 along the direction indicated by arrow Y. Rollers or the like of the film convey mechanism are arranged near that portion of the main carriage 10 at the side of the wheel 18. An I.I. 26 is arranged above the main carriage 10 at the R position. The I.I. 26 is formed integrally with a cover 30 covering an opening formed in the housing of the apparatus so as to allow an I.I. 28 having a large diameter to be set thereon. An X-ray source (not shown) is arranged below the I.I. 28 with the main carriage 10 interposed therebetween. The film conveyed and held in the inner carriage on the main carriage by the film convey mechanism is moved into the R position, and X-ray radiography is performed when the main carriage 10 is advanced in the direction indicated by the arrow X. Then, the main carriage 10 is retracted to the F position in the X direction. After photography, the film is transferred to the film convey mechanism at this F position and is stored in the film store magazine.
Recently, a great demand for a more compact and lightweight X-ray fluoroscopic/radiographic apparatus has arisen. In consideration of this demand, the length of the main carriage 10 along the advancing/retracting direction (X direction) is determined to have a mimimum value which is, in turn, determined in accordance with the size of the film. In this case, since the rail 22 for the front right wheel 16 of the main carriage 10 is disposed outwardly from the rail 24, it does not interfere with the I.I's ability to detect X-rays. However, the distal end of the rail 24 disposed inwardly from the rail 22 is very close to the input field from view of the I.I. 28. In this case, when an I.I. 28 having a large input diameter is mounted for achieving a highly accurate diagnosis, the distal end of the guide rail 24 extends into the input field of view of the I.I. 28 by a distance T, thus interfering with correct X-ray diagnosis. However, if the guide rail 24 is located at an outward position or the length of the main carriage 10 along the X direction is elongated to place the wheel 18 at a rearward position, the overall apparatus becomes bulky.